1. Field of the Invention
The invention relates to an intermittent coating system and an intermittent coating method for coating a surface of a substrate with a coating agent in an intermittent manner along a conveyance direction of the substrate.
2. Description of Relevant Art
FIG. 1 illustrates a conventional intermittent coating system C1. The coating system C1 is for intermittently coating an electrode substrate 3 of a lithium ion secondary battery, with of an electrode composite material as a coating agent 7. The substrate 3 is wound on a roller 1, to be conveyed in a direction A, and the coating agent 7 is applied thereto from a slit die 5 arranged at a side of the roller 1.
The slit die 5 has a supply flow path with a delivery opening at the end and, into this flow path, the coating agent within a tank 9 is fed by action of a pump 11. An open/close valve 15 is installed on a piping 13 upstream the slit die 5 and is controlled by a controller 17. The controller 17 detects a non-coated part of the intermittently coated substrate 3 by a sensor 19 and controls the open/close timing of the valve 15, thereby forming a non-coated part. The slit die 5 is rotatable about a support shaft 20 from a solid-line position a two-dot chain line position.
FIG. 2 illustrates another conventional intermittent coating system C2. This intermittent coating system C2 is arranged such that on a substrate 23 that is conveyed in a B direction while being wound on a roller 21 there is coated a coating agent on a coating roller 25 that rotates in the reverse direction. A doctor knife 29 is disposed above the coating roller 25.
When moving a end of this knife 29 toward or away from the coating roller 25, the coating agent is intermittently adhered on the coating roller 25 and, by transferring this coating agent on the substrate 23, an intermittent coating process is executed.
When having interrupted the supply of the coating agent by the open/close valve 15 in the coating system C1, a coating drip occurs from the delivery opening due to the residual pressure in the supply flow path and as a result it is difficult to obtain a coat film having a uniform thickness. When rocking the slit die 5 to the two-dot chain line in order to prevent this, a larger length of time is needed for the execution of the coating process to that extent, with the result that the productivity is decreased.
In addition, the coating agent is coated on the substrate 3 on the roller 1 and therefore the coating form is a type of one-side surface coating. Further, intermittent control is performed by sensing the non-coated part. Therefore, it is difficult to increase the coating speed and thereby compensate for the decrease in the productivity.
Further, when having restarted the supply of the coating agent by opening the valve 15, the coating agent at the end from which coating is started builds up due to the residual pressure. In this respect as well, it is difficult to obtain a coat film having a uniform thickness.
A high precision of the another coating system C2 is needed for positioning the coating roller 25 to the substrate 23 and for positioning the knife 29 to the coating roller 25. As a result, the relevant cost increases.
Further, the coating agent makes its flowing movement over the coating roller 25 and therefore the uniformity in the thickness of the coat film is impaired.
In addition, the coating form is a type of one-side surface coating as in the case of the coating system C1 and therefore this coating system C2 has a drawback in terms of the productivity.
The invention has been achieved with such points in view.
It therefore is an object of the invention provide an intermittent coating system and method which make it possible to obtain the coating speed that is relatively high, in addition make it possible to form a coat film having a uniform thickness, and make it also possible to realize this at a relatively low cost.
It is also an object of the invention provide an intermittent coating system and method which provides a relatively high productivity.
According to an aspect of the invention, there is provided an intermittent coating system which comprises a coating agent source that delivers a coating agent at a constant flow rate, a flow path that guides the coating agent thus delivered, a die unit that coats the coating agent supplied from the flow path on a surface of a substrate, an accumulator that is communicating with the flow path and accumulates the coating agent at an upstream position of the die unit, and a controller that controls the volume of the accumulator.
According to this aspect of the invention, the coating agent delivered from the coating agent source, whose flow rate is fixed, is guided along the flow path and is supplied to the die unit at the flow rate that corresponds to a change in the volume of the accumulator communicating with this flow path at the upstream position of the die unit and thus is coated on the surface of the substrate.
If the volume of the accumulator is fixed, the coating agent whose flow rate is fixed is supplied to the die unit and the coat film formed thereby becomes uniform in thickness. If the volume of the accumulator is increased, the coating agent is drawn thereinto, whereby the supply thereof to the die unit is interrupted. And as a result the intermittent coating becomes possible. If the volume of the accumulator is largely changed, it is possible to draw in the coating agent part that is being supplied to the downstream side as well as the increment in the amount of the coating agent supplied from the upstream side. And as a result neither drip nor fall of the coating agent from the die unit occurs and the end edge of the coat film becomes defined or sharpened. The coating agent thus drawn in may be recovered at the non-coating time or may partly be used for shaping at the coating start time. The present system performs the intermittent coating process through the control of the flow rate and therefore can execute a relatively high precision coating at a relatively low cost.
Preferably, the accumulator is comprised of an accumulation chamber and a fitting member that is slidably fitted into the accumulation chamber and the controller includes a drive mechanism for driving the fitting member.
Preferably, the fitting member comprises a piston member, a rubber plate member or an elastic plate number.
Preferably, the drive mechanism includes a cam corresponding to an intermittent cycle and a cam follower that is engaged with this cam.
Preferably, the system further comprises another flow path that guides the coating agent delivered at a constant flow rate, another die unit that coats the coating agent supplied from this another flow path on a reverse surface of the substrate, and another accumulator that is communicating with the another flow path and accumulates the coating agent at the upstream position of the another die unit.
According to another aspect of the invention, in order to attain the above object, there is provided an intermitted coating method which comprises the steps of discharging a coating agent at a constant flow rate, guiding the delivered coating agent along a flow path and supplying it to a die unit, coating the coating agent supplied to the die unit on a surface of a substrate, and accumulating the coating agent guided along the flow path at an upstream position of the die unit and thereby interrupting the supply thereof to the die unit and thereby dwelling the coating thereof on the surface of the substrate.
In order to attain the above object, according to still another aspect of the invention, there is provided an intermittent coating system, wherein a die unit for coating a coating agent on an obverse surface of a substrate being conveyed is disposed close to the surface of the substrate, and provided with a coating agent supply flow path having an open delivery port, and an accumulation piece located on a way of the coating agent supply flow path and reciprocatingly movable between a coating agent supply position for supplying the coating agent on the surface of the substrate in a state located close to the coating agent supply flow path and a coating agent supply interrupt position for forming a coating agent suction space communicating with the coating agent supply flow path in a state spaced off from the coating agent supply flow path to dwell supplying the coating agent on the surface of the substrate.
According to this construction, in a state where the accumulation piece is kept moved to the coating agent supply flow path, the coating agent that flows through the coating agent supply flow path is delivered from the delivery port and is supplied to the substrate and coated. On the other hand, when the accumulation piece is moved away from the coating agent supply flow path and the coating agent solution space is thereby formed, the coating agent that flows through the coating agent supply flow path is into this coating agent suction space and does not flow to the delivery port, whereby the supply thereof to the substrate is dwelled. By performing the supply of the coating agent on the substrate and the dwelling of this supply through the reciprocating movements of the accumulation piece, the substrate that is being conveyed has the coating agent intermittently coated thereon in the direction of the conveyance thereof, intermittent coating is executed.
Namely, the supply of a coating agent on the substrate and the dwelling of this supply made for the purpose of intermittent coating process are performed by causing the coating agent in the vicinity of the delivery port to be drawn into the coating agent suction space formed by the reciprocating movements of the accumulation piece. Therefore, the coating drips from the delivery port and the buildups of the coat film at the time when starting the formation of the coated parts do not occur, with the result that a smooth and high precision coat surface is obtained and also the time lag of the coating speed does not occur, with the result that the productivity is enhanced. Also, since the coating system is made into a structure wherein the accumulation piece is reciprocatingly moved, nor is it necessary to perform a high precision machining to such an extent as to make it difficult to manufacture the system.
According to another aspect of the invention, the delivery port of the coating agent supply flow path is provided over an almost entire width of the substrate and, in correspondence therewith, the accumulation piece and the coating agent suction space are also provided over an almost entire width of the substrate.
According to this construction, the intermittent coating process is executed over an almost entire width of the substrate and this makes it possible to obtain a smooth coat surface.
According to another aspect of the invention, the coating agent suction space is provided in the vicinity of the delivery port of the coating agent supply flow path.
According to this construction, the coating agent supply flow path between the delivery port thereof and the coating agent suction space becomes short, with the result that the coating agent flowing through this supply flow path part is reliably drawn into the coating agent suction space side. As a result, a smoother coat surface is obtained and higher precision intermittent coating becomes possible.
According to another aspect of the invention, the die unit is provided with a regulating part that stops the movement of the accumulation piece to a coating agent supply flow path side, and the accumulation piece is pressed against the regulating part side by a spring and is moved to a side opposite to the regulating part side against the elastic force of the spring by means of a cam.
According to this construction, in a state where the accumulation piece is pressed by the spring and brought into abutment with the regulating part, the coating agent that flows through the coating agent supply flow path is supplied on the substrate through the delivery port. On the other hand, through the movement of the accumulation piece made by the cam in the direction of its being moved away from the coating agent supply flow path, the coating agent suction space into which the coating agent is formed, with the result that the supply of the coating agent on the substrate is dwelled. Accordingly, the accumulation piece is reliably reciprocated by actions of the cam and spring and this makes it possible to perform a higher precision intermittent coating.
According to another aspect of the invention, the accumulation piece is pressed to a side opposite to the side wherein the coating agent supply flow path is located by means of a spring and is moved to the coating agent supply flow path side against the elastic force of the spring by means of a cam.
According to this construction, in a state where the accumulated piece is kept moved to the coating agent supply flow path side being pressed against the elastic force of the spring by means of the cam, the coating agent that flows through the coating agent supply flow path is supplied on the substrate through the delivery port. On the other hand, through the movement of the accumulation piece made by the spring in the direction of its being moved away from the coating agent supply flow path, the coating agent suction space into which the coating agent is drawn is formed, with the result that the supply of the coating agent on the substrate is dwelled.
When the accumulation piece is moved from the coating agent supply dwelling position thereof to the coating agent supply position thereof, it is gently pressed by the cam and as a result of the coating agent in the coating agent suction space is gently extruded, with the result that a higher position coat surface can be obtained.
According to another aspect of the invention, the die unit is disposed in pair so as to oppose the substrate and the resulting one pair of die units are so constructed as to coat a coating agent on both surfaces of the substrate.
According to this construction, the intermittent coating to the conveyed substrate in the direction of the conveyance thereof can be executed to both surfaces simultaneously by the set of die units disposed on both sides of the substrate and this can contribute by enhancing the productivity.
In order to achieve the above object, according to the another aspect of the invention, there is provided an intermittent coating system comprising a die unit for coating a coating agent on a surface of a substrate that is being conveyed, which die unit is disposed by being located closely to the surface of the substrate, the die unit being equipped with a coating agent supply flow path whose delivery point is open toward the surface of the substrate and being provided with an elastic plate constituting part of a flow path wall at a midway position of the coating agent supply flow path, which elastic plate is displaceable between its coating agent supply form for supplying the coating agent on the surface of the substrate and its coating agent supply interrupt form of forming a coating agent suction space communicating with the coating agent supply flow path in a state of its being displaced to the coating agent supply form in the direction of its being moved away from the coating agent supply flow path to thereby dwell the supply of the coating agent on the surface of the substrate.
According to the coating system having this construction, when the flexible plate takes its coating agent supply form, the coating agent flowing through the coating agent supply flow path is delivered from the delivery port and is supplied on the substrate and thus coated thereon. On the other hand, when the elastic plate is in its coating agent supply interrupt form wherein the elastic plate is displaced in the direction of its being moved away from the coating agent supply flow path to thereby form the coating agent suction space, the coating agent flowing through the coating agent supply flow path is drawn into the coating agent suction space and does not flow into the delivery port and the supply thereof on the substrate is dwelled. By executing the supply of the coating agent on the substrate and the interrupt of this supply through the reciprocating deformation movement of the elastic plate made in this way, the substrate that is being conveyed has the coating agent intermittently coated thereon in the direction of the conveyance thereof, whereby the intermittent coating is performed.
Namely, the supply of the coating agent on the substrate and the interrupt of this supply for executing the intermittent coating are executed by drawing the coating agent in the vicinity of the delivery port into the coating agent suction space formed by the reciprocating deformation movement of the elastic plate. And therefore the coating drips from the delivery port and the buildups of the coat film at the time of starting the formation of the coated parts do not occur, with the result that a smooth high precision coat surface is obtained and the time lag of the coating speed does not also occur, whereby the productivity is enhanced. Also, since the system is made into a structure wherein the elastic plate is reciprocatingly moved by its deformation, it is also not necessary to perform high precision machining to such an extent as to make it difficult to manufacture the system.
According to another aspect of the invention, the elastic plate is fixed at its peripheral edge to the die unit and is connected at its central part to a piston member that is movable in the direction of its being moved toward or away from the coating agent supply flow path.
According to this construction, through the movement of the piston member made in the direction of its being moved toward or away from the coating agent supply flow path, in a state where the elastic plate has its peripheral edge fixed to the die unit, the elastic plate is displaced between its coating agent supply form and its coating agent supply interrupt form wherein the central part thereof is disposed to this coating agent supply form in the direction in which it is moved away from the coating agent supply flow path.
According to another respect of the invention, the piston member is moved by being urged in the direction of its being moved away from the coating agent supply flow path by a spring and, on the other hand, is moved toward the coating agent supply flow path side against the elastic force of the spring by a cam that rotates while being kept in sliding contact with the end part thereof that is on a side opposite to the side wherein the coating agent supply flow path is located.
According to this construction, in a state where the piston member has been pressed against the elastic force of the spring by the cam and moved to the coating agent supply flow path side, the elastic plate takes its coating agent supply form. At this time, the coating agent flowing through the coating agent supply flow path is supplied on the substrate through the delivery port. On the other hand, when the piston member is pressed by the spring and moved in the direction of its being moved away from the coating agent supply flow path, the elastic plate is also displaced in this direction, with the result that the coating agent suction space into which the coating agent is drawn is formed, whereby the supply of the coating agent on the substrate is dwelled.
Accordingly, the elastic plate is reliably reciprocatingly moved by its deformation by actions of the cam and spring, with the result that a high precision intermittent coating can be executed.
According to the another aspect of the invention, there is provided an intermittent coating method comprising the steps of disposing a die unit for coating a coating agent on a surface of a substrate that is being conveyed at a position close to the surface of the substrate, the die unit being equipped with a coating agent supply flow path whose delivery port is open toward the surface of the substrate and being provided with an elastic plate constituting part of a flow path wall at a midway position of the coating agent supply flow path, supplying the coating agent on the surface of the substrate with the elastic plate being made almost planar while, on the other hand, interrupting the supply of the coating agent on the surface of the substrate by displacing the elastic plate to the planar state thereof in the direction in which the elastic plate is moved away from the coating agent supply flow path and thereby forming a coating agent suction space communicating with the coating agent supply flow path and thereby drawing the coating agent into this coating agent draw-in space, and alternately performing the coating agent supply process and the coating agent supply dwelling process repeatedly to thereby form intermittently coated parts wherein the coating agent is coated on the surface of the substrate.
According to this coating method, through the reciprocating deformation movement of the elastic plate, the supply of the coating agent on the substrate and the interrupt of this supply are performed, whereby the coating agent is intermittently coated on the substrate in the direction of the conveyance thereof, namely, the intermittent coating process is executed. Thus, identical effects as those attainable with the use of the coating system are obtained.
According to another aspect of the invention, the end part on a delivery port side of the coating agent drawn into the coating agent suction space is retracted into the coating agent supply flow path by a prescribed distance from a end of a delivery port.
According to this coating method, at the time when the supply of the coating agent is dwelled, the coating agent is brought to a state where the coating agent is retracted from the end of the delivery port into the coating agent supply flow path by a prescribed distance and therefore the drips of the coating agent from the end of the delivery part can be avoided, with the result that a higher precision intermittent coating can be performed.
According to another aspect of the invention, the coating agent is supplied successively in a fixed amount to the coating agent supply flow path by coating agent supply means and the coating agent supply means supplies as the amount of supply the coating agent whose amount is one that has been obtained by subtracting the amount of the coating agent drawn into the coating agent suction space from the amount of supply that is necessary when forming a predetermined thickness of the coat film on the coated part.
According to this coated method, when discharging the coating event from the delivery port on the substrate, the coating agent is delivered from the delivery port in an amount that is obtained by adding the amount thereof drawn into the coating agent suction space to the amount thereof supplied from the coating agent supply means. Therefore, by setting the amount of the coating agent supplied from the coating agent supply means at a value obtained by subtracting therefrom the amount thereof drawn into the coating agent suction space, it is possible to obtain a predetermined coat film thickness.